Anti-spam technology companies are now reporting that about half of all Unsolicited Bulk Email (UBE) is arriving in the form of image spam. Image spam makes use of embedded image files (generally in a .gif or .jpeg format) to deliver its message or malware.

Image spam is used – and rapidly on the rise – because of the success spammers have had in bypassing spam filters with it. Standard spam filters, like those that use Bayesian and heuristic methods, are unable to “read” image files and therefore cannot perform any text analysis on the content. While text analysis is not the sole method used by most anti-spam technologies, it remains heavily relied upon in conjunction with other methods.

Spammers have also found that image spam is more effective than emails containing only text. Images grab attention and are more immediately engaging.

The problem of spam wasting email server storage space has been significantly compounded with the increase in image spam. Such spam can be up to ten times the size of text-only email. Much less image spam can fill up far more email server space.

More troubling than the resulting waste of server space, however, can be the waste of employee time. Nucleus Research has estimated that spam costs companies almost $2,000 annually per employee in wasted time and diminished productivity. Image spam stands to bump this figure higher, as it takes longer to load, longer to examine, and can maintain the viewer’s interest longer. On an individual email basis, the effect is nominal, but scaled to take into account all the image spam received over the course of a year, it adds up to a money leak for any company.

Image spam also poses considerable security risks to businesses, especially considering that it is more successful than text-only spam at prompting recipients to carry through the message’s call-to-action.

Frequently, image spam is used to upload worms, viruses, spyware, or keystroke loggers into a computer or network. Successful installation can compromise any and all data stored on a company’s computer system. User IDs, passwords, account numbers, customer information, business plans or details, and all other sensitive private information can become immediately vulnerable. A compromise of company data can be financially devastating, can destroy public trust, and catastrophic loss of data has in many instances forced businesses to close their doors permanently.

It is now crucial that businesses seek out and install anti-spam technologies that can protect their inboxes from the ever-increasing influx of image spam. The costs of receiving image spam, combined with the potential threats it poses, makes this an essential investment that more than pays for itself.